/Engine/Source/Runtime/GameplayTags/Classes/GameplayTagsManager.h
Gets a list of all gameplay tag nodes added by the specific source
void GetAllTagsFromSource ( [FName](API\Runtime\Core\UObject\FName) TagSource, [TArray](API\Runtime\Core\Containers\TArray)< [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FGameplayTagNode](API\Runtime\GameplayTags\FGameplayTagNode) > > & OutTagArray ) const